I"ve always had a very postive experince with FB and reconnecting.
I don't add anyone I don't have any kind of contact with, or if I reconnect with someone on there and then we never talk I delete them. They don't know you deleted them and if they are not talking to you it won't hurt their feelings.
I made it a rule that if I didn't talk to that person in high school, I probably wasn't going to talk to them now.

I actually just reconnected with someone I knew growing up, and we have been having a blast reconnecting and she actually has enlisted my help in creating a mental health group based off the Icarius project. We have gotten closer than we where in the past and got a chance to reconnect with someone I would have other wise missed a chance too.

Just set ground rules for yourself in accepting friend requests and stick to them, that seems to be what works best for me!